David Fifita will make his first appearance for the Kangaroos against Fiji in Brisbane on Sunday, after captaining the Prime Minister's XIII to a 60-10 victory over Papua New Guinea this month.
The South Sydney forward previously played for Tonga at the 2022 World Cup to honour his late father, who was Tongan.
Fifita said, "This time last year was very, very hard for myself and my family on a personal level," as he dealt with a recurring ankle injury at the Titans.
He was criticised by people who did not understand the seriousness of the injury, but said he had support from loved ones.
After joining South Sydney, Fifita had a strong 2026 season under Wayne Bennett, who gave him his NRL debut in 2018.
Fifita said Bennett understood him and his family, and valued the professional environment he had missed.
He will also reunite with Kevin Walters, his former Broncos assistant coach and Queensland coach when Fifita made his State of Origin debut in 2019.
Fifita said Walters had run fitness drills alongside him when he was 17 and had remained a supportive presence.
"This time I get to represent my home country," Fifita said. "I was born in Brisbane and to do it for my other side means a lot."